Conventional telecommunication networks typically include many calling areas to cover a particular geographic area, with communication trunks used to transfer calls between different calling areas. These communication trunks and calling areas can be operated by different companies, or exchange carriers, with some communication trunks used to interconnect different calling areas, often over long distances.
Voice over Internet Protocol (VoIP) technology allows phone calls to be routed over packet networks, such as the Internet, instead of over the calling areas and trunks of conventional telecommunication networks. Wireless communication devices operating in wireless communication networks are also able to place calls using VoIP technology. For example, some calls initiated by wireless communication devices may use VoIP to connect to other wireless communication devices, or to non-wireless telecommunication devices, such as conventional telephones communicating over the public switched telephone network (PSTN).
Telecommunications carriers are required by government regulations to provide emergency calling services to their customers. In North America, 9-1-1 is the official emergency phone number that callers can use to reach dispatch personnel at a public safety answering point (PSAP). When a person calls 9-1-1 from a telephone, the call is typically routed by a communication service provider to receiving equipment at a PSAP facility. A dispatcher at the facility answers the call and assists the caller with the emergency.
Frequently, PSAP operators must dispatch various types of first responder personnel to the scene of an emergency, such as firemen, police, or paramedics, to render assistance based upon the emergency communicated by the caller. Therefore, a critical concern to communication service providers is that an emergency call is routed to the appropriate PSAP that serves the location of the caller. However, determining the location of the caller can be difficult, particularly with regard to VoIP technology.